Yes, I would remind that breeds certainly do vary within a breed. The poorer, or the less-focused the breeding program, the more the variance. I include in the category of less-focused those that breed for pets and not for the particular purpose for which the breed was developed. Yes, there are breeds that were developed for no purpose other than to be a pet, and it is harder to find actual proof of the puppy's quality in these cases.
As Chris said, there are puppy tests that judge temperament, though I've found a lot of breeders get offended if you offer to administer them. Most breeders that think highly of their program will tell you what's up rather than have you tell them anything. Most of the time, at least in the case of working kennels, the breeder will profile you and decide which pup is the best match for you. Research and attend dog shows or performance events pertaining to the breed you are interested in. People are usually more than happy to tell you the good and the bad about the breed unless they are getting ready for their ring time. However, they are much less willing to speak of who is a good or bad breeder. Meeting the dam and sire are pretty useful, though certainly no guarantee. Brian Chris wrote: breeds certainly have unique temperments/personalities and qualities, but temperment also varies widely within each breed.
